Carrier 58stA090 no ignition - I have a Carrier 58stA090. I turned off the thermostat last spring, that's all I recall. The power to it was was on all summer. I turned power off and I reset the gas switch (single) per instructions and turned power back on. Electronic thermostat. No ignition when thermostat turned up.

Try connecting the wires as follows;

Red to the Rh terminal on thermostat with a jumper going to Rc

Yellow to the Y terminal

Green to the G terminal

White to the w therminal.

Now go to the furnace or air handler, whichever you have and check the wires on the low voltage terminal board.

They should be connected as follows.

Red from thermostat to the R terminal.

White on the W terminal

Green on the G terminal

Yellow on the Y terminal.

Now you will have two wires left that run to the AC condensing unit. Connect one of them to the Com on the terminal board.
Connect the other wire from the AC to the Y terminal that already has a yellow wire on it.

This should make you AC run when the thermostat calls for cool. And heat if it calls for heat.